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MoMA

CONSERVATION FAQ

Conservation_faq

The following FAQ (Frequently Asked Questions) has been compiled by the Department of Conservation.

Q. How can I learn more about dealing with art damaged by flooding?

A. Immediate Response for Collections is a document that offers guidelines for dealing with art damaged by flooding. It offers step by step measures that can be taken to conserve artworks in a variety of mediums that have been damaged by water, including library and archive collections. It also includes a list of suppliers and emergency services that can provide some of the services listed in the document.

Q. I have an outdoor bronze sculpture. How should I take care of it?

A. Bronze is an alloy of copper with other metals that modify its hardness, color, and ability to be cast into a detailed mold. When bronze is cast it is usually a gold color. After the casting and finishing is completed, the surface is often treated with chemicals and heat which patinates the metal, coloring it green, brown, black, or a combination of the colors. Foundries usually apply waxes or other coatings to the surface of a patinated outdoor bronze to protect it from pollutants. This wax may wear off in time.

We recommend annual maintenance by a professional conservator. The surface of the sculpture may be washed to remove pollutants and dirt, and waxed. If done annually, the rate of corrosion will be retarded (though not totally eliminated), and disfiguring rain streaks will be minimized.

Q. I collect twentieth-century furniture. How can I best preserve it?

A. Some twentieth-century furniture was created from non-traditional materials, such as foam, plastic, and cardboard. Frames constructed of wood or metal are generally stable; the adhesives, padding, and coverings made of twentieth-century materials may be less permanent. Once some types of synthetic fabrics and fillers have begun their deterioration, there is nothing at this time that will reverse it, but it can be slowed down.

For furniture, just as for all other types of art objects, reduce exposure to light, especially ultraviolet radiation, which seriously damages textiles, plastics, and dyes. Handle the furniture from its most stable and widest area. Simple preventative measures such as felt pads and coasters will help avoid scratching plastic and surface finishes, which are difficult and expensive to restore. Commercial cleaners and waxes should not be applied to surfaces because they may contain abrasives and solvents that will harm the finish.

Q. My solid wood sculpture is cracking in the vertical direction. What can I do?

A. The hygroscopic nature of wood means that it will take water from the atmosphere and expand, but it will contract as the humidity lessens. The direction of shrinkage is almost always around the circumference, which causes a solid piece of wood to crack vertically.

Keeping it in a steady relative humidity can stabilize the sculpture; if the wood does not absorb or release moisture, it will no longer expand or contract.

Once a wooden sculpture has been dehydrated cracks will appear, where even exposure to high relative humidity will not make the cracks close up entirely. However, conservators can fill the cracks with a variety of materials to create a unified visual impression.

Q: What should I ask for when matting and framing works of art on paper?

  • Mat board should be made from 100% rag or lignin-free cellulose. Sometimes those labelled as "museum board" or "conservation board" are not of the highest quality. Alkaline buffered boards are not sufficient if the board contains wood pulp. Photographs should not be matted with alkaline buffered boards as some prints are adversely effected by alkalinity.

  • Hinges are used to attach the work of art to the backboard of the mat. They should be made of Japanese paper, and should be adhered with wheat starch paste. Pressure sensitive adhesive tapes and pre-gummed tapes should not be used. Photographs are often attached to the mat with photo corners.
  • The frame and the mat should be deep enough to prevent the artwork from touching the glazing. A stiff backboard behind the mat protects and supports the matted artwork. It is best to use non-acidic boards. A dust seal with paper or tape is also recommended.

Q: What damage results from using poor quality mat board?

A: Avoid mat boards containing wood pulp which causes "matburn"—a darkening of the paper under the mat or at the bevel cut of the window mat. This type of stain permanently weakens the paper fibers and is not easily removed or lightened in conservation treatment.

Q: How can I protect my works on paper from light damage?

A: Even though your artwork may be framed under UV filtering acrylic sheeting, the intensity of the light and duration of exposure is a concern. Try to avoid direct and excessive daylight. Close window curtains or drape the artwork when possible. Windows can also be covered with a film or a screen that will lower light intensity and ultraviolet rays. If possible take down the artwork periodically and exchange it with another piece, allowing the work to "rest" in storage. The most light-sensitive materials include watercolors and gouache, modern color inks, pastels, newsprint and all color papers. It is important to remember that light damage is cumulative and irreversible.

Q: How can I display or store my artwork to avoid physical damage?

  • Do not store or display works of art in areas of potentially high humidity or water leakage, e.g. basement, bathroom, outside walls, under pipes.
  • Avoid areas where temperature and humidity fluctuate, or where there is inadequate air circulation, e.g. attic and places listed above.
  • Do not hang artworks over or under radiators, heating and cooling vents, active fireplaces, humidifiers, and vaporizers.

Q: What is the cause of dark spots that sometimes appear on the paper of drawings and paintings?

A: Reddish-brown spots are known as "foxing", caused by mold or the deterioration of the metallic impurities left in the paper from the manufacturing process. Other colors of spots may be one of many types of mold damage. Mold spores are everywhere in the environment, and mold thrives on cellulosic materials, especially in conditions of high humidity (above 65% of relative humidity). Keeping artworks out of high humidity areas like bathrooms or exterior walls, can help reduce the development of such stains.

Q: If I have a work of art on paper that appears to not be flat, should I be concerned?

A: Paper is hygroscopic, reacting to changes in climate by expanding when it is humid and contracting when it is dry. A gentle undulation in the paper called "cockling" occurs under these conditions, especially with larger works. This may impair the work aesthetically as well as cause mediums such as gouache to crack or flake as it is unable to expand and contract as the paper itself does. Also, when cockling occurs under a mat, the pressure exerted by the mat can force the cockle into a crease.